Quote: teruAudacity works well for me.

Drag/drop the track you want changed into Audacity.
Select the track. It should turn blue.
Choose Effects. Scroll down to Tempo Change.
Fill in the BPM fields. Click OK.
Export the project.
Done like dinner.
My only issue with Audacity (and I’ve used it a lot) is that you can often hear that the BPM has been changed - particularly when you do large changes to the BPM.

Then again, it’s free and easy to use, so that has to count for something. :)

That worked excellently. :)
Thanks Teru!!

I heard about Audacity, but I didnt know it was free!!!

I asked this question a while back. I wound up trying to use Wavepad and got all befuddled. My question re: Audacity is - is there a noticeable pitch change with the BPM change in Audacity? Maybe that’s what Colab is talking about.

…done like dinner …very cute ;-).

is there a noticeable pitch change with the BPM change in Audacity?

No changing the tempo/BPM does not change the pitch.

I believe what collab was talking about are large changes to the BPM. There is a limit to the amount the tempo can be changed before the quality of the sound is compromised.

This is where I hope someone comes in to suggest a better program. Audacity is what I use, I don’t know any better. :)

yes, large changes in BPM will introduce audio artifacts with all of the programs I know of.

Of course all of this is done with very fancy math algorithms (formulae). I believe it’s safe to say that there are only very few algorithms, which are then used by various software makers.

The state of the art in algorithms has become better over the years. (larger BPM changes / lesser audio artifacts).

HOWEVER: There’s quite a difference between free and entry level stuff and some of the leading edge (more pricey) software.

I have hands on experience with Cubase over the last 6 major versions. And the BPM change capability has improved dramatically.

And from everything I hear, that’s the case with all of the major DAW software makers.

Oh - and just in case this isn’t obvious: It is a borderline miracle that it works as well as it does. BPM change in the old days meant you sped up or slowed down the tape. And many instruments as well as the human voice don’t lend themselves to that very well (the famous chipmunk recordings were a simple speed change). These mathematicians of sound, who create these algorithms are freakin’ geniuses. As far as I’m concerned, they deserve some patent licensing money for what they have made possible.

p.s. Most of the above holds true for pitch change software, too.

p.p.s. There’s another BPM change approach which works only for percussive material by slicing the original sample into little snippets and re-assembling it according to the new BPM. This is what’s going on with REX2 files as well as with acidized wav files.

Quote: spinmeisterHOWEVER: There’s quite a difference between free and entry level stuff and some of the leading edge (more pricey) software.
This is very true.

For instance, Audacity does a permanent change to a file, so you process a BPM change and now you have a new file with a fixed setting.
Now that I have Propellerhead Record I do the changes in the sequencer which allows me to do things like this track where the BPM goes from 110-130, and then slows down to 79 at the end - all without having to pre-process the audio file (meaning that I could undo the changes at any time, just by deleting the “tempo change” parameter).